6.9.2 to 6.9.5 format change?

I just updated pkgsrc from 6.9.2 to 6.9.5, plus rvm/rpc2/lwp, and found:
15:16:45 fatal error -- Recov_InitSeg: rvg validation failed, restart venus with -init
The release notes don't have a huge warning in call caps about client
format changes. Reading them, I don't see anything which says this.
I know I've ranted about this before, and I know coda cautions that it's
development/flaky and not to be relied on, but it would be good to have
that only as a warning rather than living up to it.
Basically, I'm asking that any storage incompatibility, even for
clients, be very loudly stated.